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Method of and apparatus for driving three-phase D.C. brushless motor

  • US 4,864,198 A
  • Filed: 01/28/1988
  • Issued: 09/05/1989
  • Est. Priority Date: 01/30/1987
  • Status: Expired due to Term
First Claim
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1. A method of directly driving a three-phase D.C. brushless motor having a rotor and only one set of three phase stator windings with first, second and third terminals by means of first, second and third bipolar driving circuits, said method comprising the steps of:

  • (A) detecting each time said rotor rotates an electrical rotational angle of 30 degrees; and

    (B) controlling said first, second and third bipolar driving circuits to successively and cyclically switch the polarities of electric potentials applied to said first, second and third terminals of said stator windings by said first, second and third bipolar driving circuits so that the following conditions occur in order, each time a rotation of said rotor by an electrical rotational angle of 30 degrees has been detected(a) said first terminal is subjected to a negative potential, said second terminal is subjected to a positive potential and said third terminal is subjected to a negative potential;

    (b) said first terminal is subjected to a negative potential, said second terminal is subjected to a positive potential and said third terminal is open;

    (c) said first terminal is subjected to a negative potential, said second terminal is subjected to a positive potential and said third terminal is subjected to a positive potential;

    (d) said first terminal is subjected to a negative potential, said second terminal is open and said third terminal is subjected to a positive potential;

    (e) said first terminal is subjected to a negative potential, said second terminal is subjected to a negative potential and said third terminal is subjected to a positive potential;

    (f) said first terminal is open, said second terminal is subjected to a negative potential and said third terminal is subjected to a positive potential;

    (g) said first terminal is subjected to a positive potential, said second terminal is subjected to a negative potential and said third terminal is subjected to a positive potential;

    (h) said first terminal is subjected to a positive potential, said second terminal is subjected to a negative potential and said third terminal is open;

    (i) said first terminal is subjected to a positive potential, said second terminal is subjected to a negative potential and said third terminal is subjected to a negative potential;

    (j) said first terminal is subjected to a positive potential, said second terminal is open and said third terminal is subjected to a negative potential;

    (k) said first terminal is subjected to a positive potential, said second terminal is subjected to a positive potential and said third terminal is subjected to a negative potential; and

    (l) said first terminal is open, said second terminal is subjected to a positive potential and said third terminal is subjected to a negative potential;

    whereby a revolving magnetic field which rotates 30 degrees step by step is produced.

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